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Date:   Fri, 31 May 2019 11:26:34 +0300
From:   Peter De Schrijver <pdeschrijver@nvidia.com>
To:     Dmitry Osipenko <digetx@gmail.com>
CC:     Daniel Lezcano <daniel.lezcano@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Joseph Lo <josephl@nvidia.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        <linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        Nicolas Chauvet <kwizart@gmail.com>
Subject: Re: [PATCH v3 0/8] NVIDIA Tegra clocksource driver improvements
Message-ID: <20190531082634.GA6070@pdeschrijver-desktop.Nvidia.com>
References: <20190524153253.28564-1-digetx@gmail.com>
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On Fri, May 24, 2019 at 06:32:45PM +0300, Dmitry Osipenko wrote:
> Hello,
> 
> This series primarily unifies the driver code across all Tegra SoC
> generations. In a result the clocksources are allocated per-CPU on
> older Tegra's and have a higher rating than the arch-timer, the newer
> Tegra210 is getting support for microsecond clocksource and the driver's
> code is getting much cleaner. Note that arch-timer usage is discouraged on
> all Tegra's due to the time jitter caused by the CPU frequency scaling.

I think the limitations are more as follows:

Chip	timer		suffers cpu dvfs jitter		can wakeup from cc7
T20	us-timer	No				Yes
T20	twd timer	Yes				No?
T30	us-timer	No				Yes
T30	twd timer	Yes				No?
T114	us-timer	No				Yes
T114	arch timer	No				Yes
T124	us-timer	No				Yes
T124	arch timer	No				Yes
T210	us-timer	No				Yes
T210	arch timer	No				No
T210	clk_m timer	No				Yes

right?

Peter.